In recent years the demand for high energy density batteries has increased. To provide high energy density batteries a plurality of anodes and cathodes separated by an electrolyte, containing a separator material or a polymeric electrolyte are arranged in stacks with the current being taken off from the electrodes with current collectors. It is desirable that these stacked cells can be rapidly fabricated while at the same time having assurance that the anode and cathodes are constructed to avoid direct electrical contact between the anode and cathodes, thereby shorting out the cells. Additionally, it is desirable that the stack of cells withstand the abuse received in their environment of use.
Accordingly, cell stacks have been fabricated from relatively flexible anodes and cathodes separated by a liquid or paste electrolyte contained in a flexible, porous separator material compatible with the electrolyte or separated by a solid polymer electrolyte which retains its structural integrity. For example, application WO 9407276-A1 describes an electrochemical cell stack comprising a continuous laminate web, having one continuous first polarity electrode layer, one continuous electrolyte layer, and a number of discrete second polarity electrode segments secured on top of the electrolyte layer in predetermined locations. The continuous laminate web is fan-folded at predetermined fold positions such that the second polarity electrode segments contact the electrolyte layer on the top and bottom sides of each of the second polarity electrode segments. The web forms a stack having first and second sides.
Additionally, U.S. Pat. No. 4,092,464 describes a high energy density flexible cell or battery capable of undergoing flexular stress with little effect on its discharge properties either during or after subjection to stress comprising a flexible anode folded over a cathode.
There is a continuing need for improved high energy density cells or batteries which are relatively flexible, capable of rapid construction, have high integrity with regard to shorting out of the cells or battery with good electrolyte stability including leakage and which is of relatively low cost.